In recent years, various magnetic tape cassettes applicable to recording and/or reproducing apparatus with rotary heads have been proposed. The construction of one typical magnetic tape cassette recently developed and proposed and applicable to recording and/or reproducing apparatus of the type having a rotary head is disclosed in the U.S. Pat. No. 4,908,723, published Mar. 13, 1990, U.S. Pat. No. 4,780,775, published Oct. 25, 1988, and U.S. Pat. No. 4,868,693, published Sep. 19, 1989. The recording and/or reproducing apparatus includes a rotary head, a tape loading device and so forth.
As is well known, the tape loading device extracts a length of magnetic tape from a magnetic tape cassette and moves the length of magnetic tape to a position that precisely wraps around a drum having rotary heads and drives the tape. Tape loading device generally comprises: movable guide posts, movable blocks with tilting posts, and guide rollers for extracting the length of magnetic tape and guiding the magnetic tape; a pinch roller and a capstan for controlling the tape speed; and a tension post for controlling the tension of the magnetic tape. In different operating modes, such as an unloading mode, a high speed and/or stop mode, and a playing mode for recording and/or reproducing, the different members of the tape loading device will move the extracted length of magnetic tape to various predetermined positions relative to the rotary head according to the selected operating mode of the magnetic tape recording and/or reproducing apparatus.
The conventional method for driving the different members of the tape loading device is by cam gear transmission associated with levers. For instance, in U.S. Pat. No. 4,868,693, Tsutsumi et al. use drive gears with cut-outs and lost-motion mechanisms to achieve this work. It is more clearly shown in FIG. 6 through FIG. 20d in the specification. In U.S. Pat. No. 4,780,775, Hirose et al. use cam arrangements as shown in the figures in the specification. In U.S. Pat. No. 4,908,723, Ohyama et al. utilize two loading rings which are substantially two gears. These complicated drive arrangements comprise gears and cams which lead to high manufacturing costs and extra large size, and further seriously increase the difficulty in assembling, due to the complicated phases of their gears and cams.